The 4400 came out before Heroes and is, on the surface, a very similar series. In fact both stories are obviously heavily influenced by the same source materials, comic books with the (relatively modern) emphasis on superhero societies as opposed to individual heroes (X-Men, Astro City, Watchmen, etc). Many people, whose only exposure to these sorts of stories have been on film and T.V., have even accused Heroes of copying 4400 but that's not true, both gleefully 'borrow' core concepts from storylines that have been out there for decades.
The 4400 uses the same premise as the X-Files, government agents sent to investigate 'unusual' occurences, with a different occurence happening every week. The overarching story, though, is pure 'Heroes'. Why have ordinary people been given super powers, what's the agenda of the 'aliens' that seem to be manipulating them, what is the 'war' that those with the gift of prophecy are wrning of? Unlike shows like Lost that start off with a mystery but don't bother giving any real answers, 4400 always ends a season with a good revelation. So with 4 seasons in one box set you'll find lots of plot twists to keep you going.
And that's by far the best thing about this box-set. Anyone who has watched 4400 from the start will tell you that the show is as good as Heroes, Lost or X-Files, it's just never been as well known. For this reason alone this box-set is a fraction of the price you will ever see for four seasons of any of those other three shows. It's the best value out there, and if you like this sort of show you will not regret buying this.